Fire sprinkler head closure plug



Dec. 1965 w. R. DE GROOT ETAL 3,

FIRE SPRINKLER HEAD CLOSURE PLUG Filed Jan. 9, 1964 INVENTORS WALTER R.DE GROOT STANLEY LAZERU5 AGENT tributing water over a wide area.

United States Patent 3,223,171 FIRE SPRINKLER HEAD CLOSURE PLUG WalterR. De Groot, Arlington, and Stanley Lazerus,

Alexandria, Va., assignors to Atlantic Research Corporation, Fairfax,Va.,.a corporation of Virginia Filed Jan. 9, 1964,'Ser. No. 336,833 4Claims. (Cl. 169-1) This invention relates to valves and, moreparticularly, to closure plugs for fire sprinkler heads.

Automatic fire sprinkler heads commonly employed in commercialestablishments such as ofiice bulidings, warehouses, manufacturingplants, etc., include a threaded nipple which is received Within a bossprovided in overhead water supply lines. Attached to the nipple orintegrally formed therewith is a support means or bracket on the bottomof which is provided a spray plate for dis- A fusible member is insertedbetween the bracket and the nipple in such a manner as to obturate anorifice extending through the nipple and, thus, prevent water fromflowing therethrough. Upon the application of heat above a predeterminedtemperature, such as will occur when a fire breaks out, a portion of thefusible member fuses and is released from engagement with the nipple andsupport bracket permitting 'water fiow through the nipple.

Current methods for stopping the flow of water through sprinkler headsare extremely expensive and relatively difficult and awkward to employ.The most common type of shut-off plug presently used is a wedge-shapedmember which is inserted horizontally between the supporting bracket andthe nipple. In addition to the high cost, installation of these plugs isdifiicult as it requires the installer to climb up a ladder and hammerit in place while water is raining down. It also has been found thatrapid insertion of the plug within a sprinkler head frequently damagesthe sprinkler head due to the large force required to wedge the plugproperly into place, this force being applied parallel to and at adistance from the supporting means for the sprinkler head thus resultingin a relatively high moment at the juncture between the nipple and theboss.

In 'view of these disadvantages in currently available closure plugs itis an object of the present invention to provide an inexpensive closureplug which is relatively easy to install.

Another object of the present invention is to provide a closure plugwhich can be installed rapidly in a ceilingmounted sprinkler head bysomeone standing on the floor.

Further objects and attendant advantages of the present invention willbecome better understood from the fol- -lowing description.

tions. A resilient valving member is placed on one end of one ofthetelescoping members while an indentation is provided in the remote endof the other of the telescoping members. -A hole is provided in each ofthe telescoping members at such a location as to effect alignment of theholes when the telescoping members are in their contracted or shortenedposition. In this position a pin is placed through the holes to maintainthe plug normally in the contracted position.

A closure plug formed in this manner is adapted for insertion within afire sprinkler head of the type which includes a nipple and a supportmeans extending from the nipple for supporting a spray plate mountedbelow the nipple. The support means also includes a small projectionwhich extends upwardly toward the nipple and-which carries a fusiblemember. When the temperature in the immediate area of the sprinkler headexceeds a predetermined value a portion of the fusible member fuses-andthe member falls from the sprinkler head exposing the projection. Theclosure plug is inserted in the sprinkler head by placing theindentation provided in'one end of the plug on the projection. Uponremoval of the'pin, the spring-loaded telescoping members move inopposite directions causing the plug to expand and forcing the valvemember upwardly against the nipple, obturating the orifice extendingthrough the nipple and eliminating the flow of water therethrough.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as theinvention, it is believed that the invention will-become betterunderstood from the following description taken in combination with-theaccompanying drawing in which:

FIGURE 1 illustrates a closure plug, formed in accordance with thisinvention, inserted Within a fire sprinkler head.

FIGURE 2 is a sectional view of a closure plug, formed in accordancewith this invention, in its extended position.

FIGURE 3 is a partial sectional view of the closure plug of FIGURE 2 inits contracted position.

FIGURE 4 illustrates a pole used for inserting the closure plug in'afire sprinkler head.

With reference to the-drawing, and more particularly FIGURE 1, there isshown a closure plug 10 inserted within a common fire sprinkler head 12which in turn is mounted on a boss 14 provided on an overhead watersupply line 16. The tire sprinkler head 12 includes anexternally-threaded nipple 18 which is screwed intothe boss 14 and whichhasan orifice (not shown) extending therethrough through which 'thewater flows. The fire sprinkler head'12 also includes a support means orbracket 20 at the bottom of which is mounted a'spray plate 22 used fordistributing the water emanating'from the orifice over a wide area. Anupwardly extending projection :24 is also provided on the supportbracket 20 to provide a support for a fusible member (not shown)Whiclris normally mounted in the sprinkler head to prevent flow of watertherefrom. When the temperature in the imme diate area of the sprinklerhead rises to a predetermined value a portion of the fusible member.fuses and the member falls from the sprinkler head thusexposing theorifice and permitting water to flow'from the sprinkler head.

The closure plug 10 used for stopping the flowof water, illustrated inFIGURE 2, includes a pair of'telescoping members 26, 28, and resilientbiasing means 30.for normally urging the telescoping members inopposedsdirections. The first telescoping member 26 is a tubular member,preferably cylindrical, and includes a resilient valve portion'or member32, such as a rubber. cap,-mounted on one end thereof. The secondtelescoping member,:28 is. formed to slidingly fit within the firsttelescoping member 26 and has provided at the'end .29 thereofremote'from the'first telescoping member 26 a seat 33 having anindentation'34 centrally located in theouter surface. The secondtelescoping member 28 can be solid or it can'be tubular with or withoutan-end .wall on theend thereof which fits within the first telescopingmember.

The resilient biasing means 30, for example, a'compression coil spring,is located within the first telescoping member 26 so as to abut againstone end of the first telescoping member 26 and against the secondtelescoping member 28, normally urging the second member 28 in adirection effecting extension of the plug 10. Inorder to prevent thetelescoping'membersizfi, 28 from separating, a groove is provided in-theinternal surface of each telescoping member, the groove in the firsttelescoping mem her 26 being designated 35 and the groove in the secondtelescoping member 28 being designated 36. The grooves 35, 36 aresufficiently deep and wide to receive and retain one turn of the coilspring 30. The upper surface of the second telescoping member 28 can bebeveled as shown at 37 to simplify snapping the coil spring 30 in place.

A first hole 38 is provided through the wall of the first telescopingmember 26 and a second hole 39 is provided through the secondtelescoping member 28. The holes 38, 39 are so located such that theywill be aligned when the plug is in its contracted or shortenedposition, as illustrated in FIGURE 3. Restraining means or a release pin40 is inserted in the holes 38, 39, so as to normally maintain the plug10 in its contracted position. The release pin 40 need not extendcompletely through the telescoping members but need extend only so faras to maintain the plug in its contracted position. The contractedposition can also be considered the loaded position since the coilspring" 30 is compressed and, thus, is exerting a force on the twotelescoping members 26, 28, tending to force them apart.

Insertion of the closure plug 10 within the fire sprinkler head 12 isachieved by placing the closure plug Within the fire sprinkler head suchthat the extension 24 of the support bracket 20 mates with theindentation 34 provided in the seat 33 of the second telescoping member28. This arrangement will center the plug in the fire sprinkler head tofacilitate proper operation thereof. The release pin 40 is then removedand the coil spring 30 forces the first telescoping member 26 away fromthe second telescoping member 28 and forces the resilient valve member32 against the nipple 18 of the fire sprinkler head 12, thus obturatingthe orifice and eliminating the flow of water through the fire sprinklerhead. In order to block the flow of Water through the orifice the spring30 must have a compressive loading force when the plug is in itsextended position at least equal to and preferably greater than theforce exerted by water in the supply lines, whose pressure is usually inthe range of 40 to 90 p.s.i.g. and could go as low as 20 p.s.i.g.

Because mounting of the plug merely requires placing it on theprojection 24 of the fire sprinkler head and removing the release pin 40this plug is easily adaptable to mounting from the floor through use ofa mounting pole 42, illustrated in FIGURE 4. The mounting pole includesa pair of resilient fingers 44, 46, and a triggering mechanism 48, suchas a lever system or a string. The plug 10 is placed within the fingers44, 46, with the release pin 40 facing the pole 42. A hook 50 providedat the end of the triggering mechanism 48, is placed into a hole 52provided in the end of the release pin 40. The operator then places theplug 10 in position in the fire sprinkler head and actuates thetriggering mechanism 48 extracting the release pin 40 from thetelescoping members 26, 28. The spring 30 causes extension of the pluginto position to eliminate the flow of water through the fire sprinklerhead 12.

It can be seen that construction of the closure plug 10 is quiteinexpensive since there need be no closely mated, accurately formedparts and, therefore, the tolerances of the various parts may be quitelarge. It is not important to maintain a close sliding fit between thetelescoping members 26, 28, because they contain no liquid orpressurized gas. Neither is it important that the cooperating holes 38,39, in the telescoping members be accurately formed for as long as thepin 40 can be inserted therethrough the spring will force thetelescoping members apart until the walls of the telescoping memberslock the pin in place. Therefore, one hole could be considerably largerthan the other hole still allowing mounting of the pin in place Whilereducing the cost of production. The valve member 32 is constructed of aresilient material such as rubber and is formed considerably larger thanthe diameter of the orifice so that the plug will still obturate theorifice even if the plug is not accurately aligned on the projection 24.This also reduces the cost of production since the valve member need notaccurately mate with the orifice.

While one specific embodiment has been shown and described above, itwill be obvious to those skilled in the art that various changes andmodifications may be made without departing from the invention in itsbroader aspects. Therefore, it is intended in the appended claims tocover all such changes and modifications as fall within the true spiritand scope of this invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. For use in terminating flow through a fire sprinkler head of the typehaving a nipple in fluid-flow relationship with a fluid supply and aspray plate spaced from but attached to said nipple, a closure plugsolely contained between said nipple and said spray plate with theextended length of said plug, when in use, being equal to the distancebetween said nipple and said spray plate, said plug comprising (a) afirst member including a valve portion, said valve portion abutting andobturating said nipple and preventing fiuid flow through said nipplewhen said plug is in its extended position,

(b) a second member arranged in telescoping relationship with respect tosaid first member, said second member being adapted to engage said sprayplate,

(c) spring means engaging said first and said second members and urgingsaid first and said second members in opposed directions, and

(d) restraining means engaging said first and said second members fornormally maintaining said plug in a contracted position, wherebydisengagement of said restraining means permits said spring means toeffect extension of said plug.

2. A closure plug as defined in claim 1 wherein said spring means ismounted within one of said members.

3. A closure plug as defined in claim 1 wherein said restraining meanscomprises a pin adapted to be received by a first hole provided in saidfirst member and a second hole provided in said second member, saidfirst and second holes being aligned when said plug is in saidcontracted position.

4. For use in terminating flow through a fire sprinkler head of the typehaving a nipple in fluid-flow relationship with a fluid supply and aspray plate spaced from but attached to said nipple, a closure plugsolely contained between said nipple and said spray plate with theextended length of said plug, when in use, being equal to the distancebetween said nipple and said spray plate, said plug comprising,

(a) a first tubular member including a resilient valve portion, saidvalve portion being adapted to engage said nipple to prevent fluid flowtherethrough,

(b) a second member arranged in telescoping relationship with said firsttubular member, said second member having one end Wall having anindentation on the outer surface thereof adapted to receive a projectionextending from a support means, said indentation being adapted to centersaid plug in said sprinkler head,

(c) a spring mounted within said first tubular member and engaging saidfirst and second members urging said first and second members in opposeddirections, and

(d) restraining means for normally maintaining said plug in a contractedposition, said restraining means comprising a pin adapted to bereceiving by a first hole in said first tubular member and a second holein said second member, said first and second holes being aligned whensaid plug is in said contracted position whereby extraction of said pinpermits said spring to effect extension of said plug.

(References on following page) 5 6 References Cited by the Examiner2,520,588 8/1950 Wells et 211.

UNITED STATES PATENTS 2,607,429 8/ 1952 Schnorr 169-26 3/1908 G FOREIGNPATENTS ray.

6/1912 Morey 5 8,179 4/ 1912 Great Bntam. 1919 Sechrist 1 7 5 M. HENSONWOOD, 111., Primary Examiner. 7/ 1935 Bronander 169-26 EVERETT W. KIRBY,Examiner.

4. FOR USE IN TERMINATING FLOW THROUGH A FIRE SPRINKLER HEAD OF THE TYPEHAVING A NIPPLE IN FLUID-FLOW RELATIONSHIP WITH A FLUID SUPPLY AND ASPRAY PLATE SPACED FROM BUT ATTACHED TO SAID NIPPLE, A CLOSURE PLUGSOLELY CONTAINED BETWEEN SAID NIPPLE AND SAID SPRAY PLATE WITH THEEXTENEDED LENGTH OF SAID PLUG, WHEN IN USE, BEING EQUAL TO THE DISTANCEBETWEEN SAID NIPPLE AND SAID SPRAY PLATE, SAID PLUG COMPRISING, (A) AFIRST TUBULAR MEMBER INCLUDING A RESILIENT VALVE PORTION, SAID VALVEPORTION BEING ADAPTED TO ENGAGE SAID NIPPLE TO PREVENT FLUID FLOWTHERETHROUGH, (B) A SECOND MEMBER ARRANGED IN TELESCOPING RELATIONSHIPWITH SAID FIRST TUBULAR MEMBER, SAID SECOND MEMBER HAVING ONE END WALLHAVING AN INDENTATION ON THE OUTER SURFACE THEREOF ADAPTED TO RECEIVE APROJECTION EXTENDING FROM A SUPPORT MEANS, SAID INDENTATION BEINGADAPTED TO CENTER SAID PLUG IN SAID SPRINKLER HEAD, (C) A SPRING MOUNTEDWITHIN SAID FIRST TUBULAR MEMBER AND ENGAGING SAID FIRST AND SECONDMEMBERS URGING SAID FIRST AND SECOND MEMBERS IN OPPOSED DIRECTIONS, AND(D) RESTRAINING MEANS FOR NORMALLY MAINTAINING SAID PLUG IN A CONTRACTEDPOSITION, SAD RESTRAINING MEANS COMPRISING A PIN ADAPTED TO BE RECEIVINGBY A FIRST HOLE IN SAID FIRST TUBULAR MEMBER AND A SECOND HOLE IN SAIDSECOND MEMBER, SAID FIRST AND SECOND HOLES BEING ALIGNED WHEN SAID PLUGIS IN SAID CONTRACTED POSITION WHEREBY EXTRACTION OF SAID PIN PERMITSSAID SPRING TO EFFECT EXTENSION OF SAID PLUG.